Recently, there has been significant research focus on Peer-to-Peer (P2P) Massively Multiplayer Online Games (MMOGs). A number of architectures have been presented in the literature to implement the P2P approach. One aspect that has not received sufficient attention in these architectures is state persistency in P2P MMOGs. This survey presents an overview of the current challenges present in P2P MMOGs, followed by an overview of classic state consistency models used in C/S MMOGs. The survey then classifies the state persistency techniques currently used in P2P MMOGs into super peer storage, overlay storage, hybrid storage, and distance-based storage. Key characteristics, namely scalability, fairness, reliability, responsiveness, and security are then defined. Each state persistency technique is evaluated according to these characteristics and recommendations are then made of possible future areas of research into the different storage types.